Method and apparatus for the treatment of steam



Aug. 12, 1930. J. R. McDERMET 1,773,054

METHOD AND APPARATUS FOR THE TREATMENT OF STEAM Filed April 21, 1928Patented Aug. 12, 1930 UNITED STATES PATENT OFFICE JOHN B..MCDERMET, OFJEANNETTE, IENNSYLVANIA, ASSIGNOR TO ELLIOTT COMPANY, OF JEANNETTE,PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA METHOD AND APPARATUS FOR THETREATMENT OF STEAM Application filed April 21,

The present invention relates broadly to the art of steam treatment, andmore particularly to an improved method and apparatus by means of whicheither superheated or sat- 5 urated steam may be effectively treated toinsure complete desuperheating in the case of superheated steam, and theseparation of excess water in case of either superheated or saturatedsteam treatment.

It is well understood in the art to which the present invention relatesthat exhaust steam is becoming more and more highly superheated, andthat such superheated steam has only a very small proportion of theconductivity of saturated steam from the standpoint of heaterperformance. This is necessarily true since the major transfer of heatin heater condensation is from the latent heat of the steam incondensing. Inasmuch as the specific heat of saturated steam isapproximately .46 B. t. u. per pound while the latent heat issubstantially 97 0 t. u. per pound under usual conditions of operation,the advantages of desuperheating will be apparent.

In the art of desuperheating, difiiculty arises in supplying the roperamount of water for insuring comp ete saturation of the steam and inmaintaining any eflicient relationship between the quantity of water andthe quantity of steam. Obvlously, if too little water is supplied, thesteam is not completely desuperheated, and if too much water issupplied, not only is there a loss due to steam condensation, butobjectionable results may follow from the presence of excess water. Inaccordance with the present invention, I provide an improved method oftreating steam whereby the desired desuperheating is accomplishedwithout the possibility of carrying over any excess water. I alsoprovide a method and apparatus for treatment of either superheated orsaturated steam and efiective for removing all excess water therefrom.

The present invention also provides a method and apparatus for thetreatment of steam such that an intimate contact. between the steam anddesu erheating water, where supplied, is obtaine and such that anyexcess water is removed.

1928. Serial No. 271,756.

In the accompanying drawings I have shown for purposes of illustrationonly, and in a more or less diagrammatic manner, a preferred embodimentof the present invention, it being understood that the drawings are forpurposes of illustration only, and not for purposes of limitation.

In the drawings Figure 1 is a longitudinal sectional view through aportion of steam treating apparatus constructed in accordance with thepresent invention, and

Figure 2 is a top plan view of the same.

In accordance with the present invention, there may be provided aconduit 2 into which either superheated or saturated steam may beadmitted in such manner that it will flow through the conduit in thegeneral direction indicated by the arrow 3. Extending into the conduiton the up-stream side with respect to steam flow is a water jet or spraynozzle 4, herein shown as pointed lip-stream with respect to itsdischarge end 5, although the direction of discharge may be varied. Thenozzle is connected to a suitable source of water through the pipe 6.This spray nozzle may be of any desired construction for spraying waterinto superheated steam passing through the conduit.

At a point in the conduit down-stream with respect to the spray nozzleis a perforated plate 7 of truncated cone shaped configuration, the baseof the cone having a flange 8 which may conveniently be clamped betweenthe flanges 9 on adjacent sections of the conduit. The smaller end 10 ofthe cone is freely open to permit the passage of steam therethrough andinto a separating chamber 11. This chamber may be of any desired form,but is herein illustrated as provided with a series of verticallyextending guides 12, adapted to form slides for guidmg a separator 13into place therein. The separator is herein illustrated as comprisingend plates 14, connected b a cross-plate 15 intersecting the path of owof the steam The upper part 16 of the plate 15 is prefer" ably angularlydisposed, as indicated more particularly in Figure 1 of the drawings,and provided with a downwardly and inwardly turned end 17 forming atrough or collecting reservoir 18 for the purpose hereinafter described.

The separator above the end 17 provides a free passage between the endplates 14 for the steam in its travel to the outlet 19.

The separating chamber 11 at its lower portion may be formed with anopening 20 through which separated water may be drawn off to any desiredpoint.

From the foregoing description, it will be apparent that in case ofsuperheated steam, it enters from the right hand end of the conduit asviewed in the drawings and successively passes the nozz1e.4, the cone 7,and the separator 13. As it passes the nozzle it receives the waterinjected thereby in the form of a fine spray so that it passes on fromthe nozzle in the form of a mixture. It is this mixture which is actedupon by the cone and separator.

The sequence referred to is important, but it will be apparent that thedistances and relative arrangement of the different parts may beconsiderably varied, the distance between the nozzle and the cone, forexample,

being capable of an extremely wide variation,

and the distance between the cone and the separator being capable of aconsiderable variation. The particular construction of the cone, nozzleand separator may likewise be varied, as will be apparent from thefollowing description.

In operation, the mixture leaving the nozzle comes to the large end ofthe cone which has a diameter D approximately e ual to the insidediameter of the conduit. T e area of the outlet end 10 of the cone ismaterially less, it having a much smaller diameter d.

This change in flow area presented by the cone necessarily acceleratesthe velocity of the mixture passing therethrough, and passes the mixtureonward to the separator, through the conduit, in the form of a streamhaving a smaller cross-sectional area than the area of the conduit, andtraveling at a higher velocity than the mixture intermediate the nozzleand the cone. This stream of high velocity mixture is in realitysurrounded by an annulus composed of a steam and water mixture at thesame pressure and tern erature of the high velocity stream, but di ercnttherefrom in that it is relatively quiescent.

In passing throu h the cone, the mixture is necessarily compel ed toimpinge thereon in such manner that part of it passes through theperforations in the cone and forms the relatively quiescent annulusreferred to, while the remainder is concentrated through the open end,and forms the high velocit stream.

The restriction in the area 0 the cone and the increased velocityreferred to impose a pressure drop through the cone which is effectivefor forcing steam and entrained wateroutwardly through the perforations,this action resulting in a series of relatively small jets extendingradially of the cone and substantially normal to the surface thereof.The water entrained in the steam over that portion of the arearepresented by the difference in the diameters D'and d is deposited uponthe surface of the cone, and immediately projected into the quiescentarea of the low velocity stream in the manner referred to.

The cone thus functions to collect the water suspended in what may betermed the outer annulus of the mixture, and disposes of it in either oftwo manners. The first of these may be considered as a redistribution ofthe water in part into the central stream of high velocity steam. Suchredistribution is desirable since it accomplishes an intimate contactand further intermingling of the steam and water.

Secondly, such water may be projected mechanically, in the mannerreferred to, through the openings in the cone into a region ofcomparatively quiescent flow. In this manner, it enables any surpluswater to precipitate or separate onto the conduit surface,-run down intothe bottom thereof, and thence into the separator and out of the opening20. These actions directly take place as the result of the constructionof the cone. It also functions, as set forth, to provide a high velocitystream and a low velocity annulus, which enables any surplus waterdeposited from the fast moving stream to automatically arrive in theslow moving annulus, giving it a further chance to separate and run intothe separator.

The construction possesses a further advantage in that it enables aseparator of relatively smaller size to be utilized, the separatorhaving imposed thereon a much easier separating duty in terms ofquantity than would be the case under different conditions of operation.This will be appreciated when it is considered that the separator, dueto the concentration of the major portion of the water in the highvelocity central stream, has to operate over a much smaller area thanwould be the case if the entire area of the conduit were filled with auniform mixture.

Since the stream carrying the water in suspension is of much less areathan the inside diameter of the conduit, thecapacity of the separator interms of conduit area is substantially increased. Thus, a relativelysmall separator may take care of the flow through a relatively largeconduit.

In'addition to the above, regardless of the construction of theseparator, it necessarily has impinging thereon two streams movingvelocity.

tor herein disclosed further contributes toward. the attainment of thedesired result of uniform water distribution within-the entire mass ofsteam, together with the separation of any surplus moisture.

This is true for the reason that the water thrown at high velocityagainst the Separator travels upwardly into the trough 18, out of thepath of the steam, while the steam is permitted to flow upwardly aroundthe trough to the outlet 19. Any slower moving water content impingingagainst the separator may flow downwardly directly into the bottom olthe separating chamber.

The apparatus hereinbefore described functions in the manner set forthwhensaturated steam is being treated for the se aration of excess water,it being understoo that in such cases the discharge nozzle is notutilized.

It will be apparent to those skilled in the art that the present methodand apparatus enables large quantities of steam to be ell'ectirelytreated without any undue restriction to the low thereof, the conditionsof treatment being such that the entire body of steam is given ampleOpportunity for contact with water under such conditions as to effect anintimate and uniform intermixing thereof for purposes of destroying thesuperheat. and under such conditions, that free or surplus water is notcarried over into the outlet 19 and thence to other'a-pparatus' in whichthe dcsuperheated steam is to be utilized.

" Changes, as herein referred to, may be made in the construction andoperation of the apparatus without departing from the SpH'lt of myinvention or the scope of my broader claims. v

' I claim:-

' 1. Steam treatment apparatus, comprising a steam conduit, meansfor'supplying water thereto, a separator for surplus water, and meansintermediate the point'of water supply and separator for producing sideby side flow zones having different velocity characteristics, o

2. Steam treatment apfparatus, comprising a steam conduit, means orsupplying water tl ereto, a separator for surplus water, an meansintermediate the point of water supply and separator for producing*aflow zone of high velocity, and 1f flow zone substantially.

concentric thereto and of relatively lower 3. Steam treatment apparatus,compris-,

'- ing a steam conduit, means for supplying water thereto, a separatorfor surplus water, and means intermediate the point of water supply andseparator for producing a flow zone of highv velocity. and a flow zoneof rela-,

tively lower velocity, with the higher velocity zone within the lowervelocity zone.

4.Stea-m treatment apparatus, comprising a conduit for steam, a watersupply means in the upstream end of said conduit, a separator in thedownstream end of said conduit, and a velocity increasing means at anintermediate noint in said conduit, said velocity increasing means beingconstructed and arranged for increasing the velocity of a part only ofthe flow through the conduit.

5. Steam treatment apparatus, comprising a conduit for steam, a watersupply means in the up-streamend of said conduit, a separator in thedown-stream end of said conduit,

separator a steam and water mixture comprising zones traveling atdifferent velocities, said zones being delivered to said separatorsimultaneously.

7. Steanrtreatment apparatus, comprising a separator, and means fordelivering to said separator a steam and water mixture comprising zonestraveling at diflerent velocities, with the high velocity zone withinthe lower velocity zone, said zones being delivered to said separatorsimultaneously.

8. In the method of treating steam, the steps comprising suppl ing-waterthereto, increasing the velocity 0% a portion only thereof, andsubjecting the steam and water mixture at high velocity to the action ofa, separator.

9. In the method of treating superheated steam, the steps comprisingsupplying dc-- water .from the high velocity stream into the lowvelocity stream, and causing both said streams to impinge against aseparator.

11. In the method of treating superheated steam, the steps comprisingsupplying desuperheating water thereto, effecting a radial movement 7 ofwater outwardly from the inner steam and'water mixture zone intoan outerzone containing steam, and'thereafter subjecting-the entire mixtureincluding both zones to the action ofaseparator.

12. Separating apparatus, comprising aconduit, a water supply means inthe up stream end of said conduit, a se arato'r 1n the down stream endof said con uit ,and a 7 locity, completely confinin 1 irg substantiallypoint intermediate said water supply and separator and effective forincreasing the velocit of a part only of the flow through the con uit. U

13. Treatment apparatus, comprising a conduit, means for supplying waterthereto, a separator for surplus water, and means intermediate the pointof water supply and separator for producing overlapping substantiallyparallel flow zones having different velocity characteristics.

- 14. Treatment apparatus, comprising a conduit, means for supplyingWater thereto, a

separator for surplus Water, and perforated means intermediate the pointof water supply and separator for producing overlaparallel flow zoneshaving i erent velocity characteristics.

15. In the method of treating steam, the steps comprising deliveringwater thereto, transforming the resulting mixture into a zone of highvelocity and a zone of low veboth zones and insuring continued travel tereof, and cansing both said high and low velocity zones to im ingeagainst a separator.

11 testimony whereof I have hereunto set my hand.

JOHN R. McDERMET.

